Group B Streptoccus type III (GBS) studies - Antepartum penicillin therapy in pregnant rhesus monkeys infected intraamniotically with GBS significantly reduces neonatal mortality and associated morbidity. Herpes encephalitis - We have had difficulty in reproducing our results in the rhesus Macaca mulatta and cynomologus Macaca fascicularis monkeys. We have obtained a new "low passage" strain that is extremely virulent in hooded rats. We will inoculate monkeys with this virus. Varicella-like "Delta Agent" encephalitis - The Delta herpes virus (DHV) will produce encephalitis and pneumonia in young DHV antibody negative patas monkeys Erythrocebus patas. This model can be used to study pathogenesis, diagnosis and treatment of human varicella encephalitis.